It's official. Starting Sunday, you can get an iPhone at Wal-Mart. As is their trademark, the prices will be lower than elsewhere, but only by $2. I guess you can buy a couple of apps with the money you save!
Or, if you don't mind a refurbished unit (and Apple does a great job with their refurbs), AT&T has 8GB iPhones for just $99. That's a great deal. But with MacWorld in just over a week, and rumors of new iPhones (either larger capacities or the much less likely iPhone Nano), it might be wise to wait. Of course, you could leverage AT&T's return policy, so you could act now and see what happens.
http://www.wireless.att.com/cell-phone-service/cell-phones/refurb-phones.jsp